Pipe handling unit

ABSTRACT

A pipe-gripper is adapted for connection to a manipulator for the handling of a pipe or a pipe stand. The pipe-gripper has an elongated housing; a rotor supported in the longitudinal housing, provided with a periphery and a longitudinal groove, the longitudinal groove having an inside face and a groove mouth having a width, and the rotor being rotatable around its center axis; a toothed rim arranged on the periphery of the rotor and being interrupted by the longitudinal groove; a clamp assembly comprising at least one clamping device arranged within the rotor; a rotor drive being positioned within the elongated housing; and a rotor transmission in engagement with the rotor drive at toothed-rim engagement points at a distance between the toothed-rim engagement points larger than the width of a groove mouth.

FIELD

The invention relates to a pipe-gripper arranged to be connected to a manipulator for handling a pipe or a pipe stand.

BACKGROUND

In the assembling and disassembling of a pipe string, for example a drill string that is used for drilling in hydrocarbon-bearing underground structures, many apparatuses and operations connected with moving, rotating and mounting the pipe string, pipe stands and single pipes are used. Conventionally, operations including screwing together pipes, making up and breaking out pipe joints have been carried out by means of cooperating backup tongs and power tongs, possibly by the cooperation between a drilling machine or another drilling unit and a backup tongs, while the pipes have been moved between the pipe-string centre and a pipe rack by means of one or more manipulators firmly holding the pipes and orienting them. Traditional pipe-grippers are unable to provide the required torque to make up/break out pipe joints.

SUMMARY

The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.

The object is achieved through the features that are specified in the description below and in the claims that follow.

The invention provides a pipe-gripper which, in addition to being able to hold a pipe or a pipe stand in a firm grip to orient and move the pipe or pipe stand, is also arranged to rotate the pipe or the pipe stand around the pipe centre axis to screw the pipe or the pipe stand together with a pipe string by supplying makeup torque while extending the pipe string, or to screw a pipe together with another pipe during the assembling of a pipe stand, and to reverse the process when disassembling the pipe string or pipe stand using breakout torque on a pipe joint. The pipe gripper may be connected to a manipulator arm using a manipulator arm joint.

The pipe-gripper comprises an elongated housing wherein a rotor is arranged. The rotor may extend out through end openings in the elongated housing. A longitudinal groove arranged to accommodate a portion of a pipe or a pipe stand (herein after referred to as “pipe”) extends through the entire length of the rotor. The rotor is supported in the housing. The elongated groove has a centre axis preferably coinciding with the centre axis of the rotor. The elongated groove is provided with side faces extending out from bottom portion. Preferably, the longitudinal groove is U-shaped and is provided with a circularly rounded bottom portion and parallel side faces extending tangentially from the rounded bottom portion. In a gripping position, in which the pipe-gripper may be moved into engagement with the pipe or pipe stand, a lateral opening in the housing forms a complementary, radial extension of a mouth of the longitudinal groove of the rotor.

The rotor is provided with an external toothed rim interrupted by the longitudinal groove. A rotor drive, which is arranged in a portion of the housing, engages with the toothed rim via a rotor transmission assembly, the points of engagement of the driving wheels with the toothed rim being spaced apart by a distance which is larger than the mouth width of the rotor, in order thereby to ensure that the rotor drive will be in engagement with the toothed rim at all times. Preferably, the toothed rim is arranged in an end portion of the rotor.

The rotor is provided with at least one set of clamping devices which, when being displaced radially, are arranged to engage with a portion of the pipe or the pipe stand when this is placed in the longitudinal groove of the rotor. Each set of clamping devices may include at least two diametrically opposite dies arranged in the transition between the bottom of the groove and the side faces of the groove. The dies are movable along respective guides, preferably in the form of ramps in the rotor, to, by axial displacement, achieve the radial displacement. The rotor is preferably provided with two sets of clamping devices arranged remotely from each other. It is an advantage if the sets of clamping devices have the same direction of motion and that the direction of motion, in engaging with the pipe, is in the downward direction seen in the vertical position of the pipe-gripper, so that gravity helps to lock the pipe in the rotor by pulling the pipe-clamping dies downwards and inwards. The at least one set of clamping devices are connected via transmission means to an actuator arranged in the housing. It is an advantage if each set of clamping devices is connected to a separate actuator, for each set of clamping devices to provide the desired engagement with the pipe independently of variations in pipe diameter, wear on the pipe-clamping dies, deformation of the guide tracks, etc. The actuator is preferably formed as a second drive motor which is connected, via a clamp transmission arranged in the longitudinal housing, to threaded rods via rows of gear wheels arranged on an end face of the rotor, the threaded rods extending in an axial direction into engagement with the dies, typically via threaded holes in axially displaceable die carriers. A remote-controlled drive coupling forms a transmission interface between the housing and the rotor for uncoupling the drive motor so that the rotor may be rotated freely relative to said drive motor. The drive coupling may be provided with a coupler motor may be adapted to move the drive coupling.

In an alternative embodiment of the invention, the dies are connected to brace rods arranged in the axial direction of the rotor and connected to a mounting which is rotatable around the centre axis of the rotor and is axially displaceable by means of a linear actuator, for example a so-called linear motor.

If several sets of clamping devices are connected to one and the same actuator, it is an advantage if a resilient element is arranged in the connection between each set of clamping devices and the clamp transmission so that a sufficient pressure is achieved from each set of clamping devices against the pipe to be held fixed. The resilient element may be formed as a coupling element for said threaded rods or brace rods of the pipe grippers, the coupling elements being displaceable in the axial direction of the rotor against tensioned springs.

The pipe-gripper is provided with a mounting for rotatable connection to a manipulator with several degrees of freedom for manoeuvring the pipe-gripper within a work area. Preferably, the mounting is arranged in the middle portion of the housing.

The invention is defined by the independent claim. The dependent claims define advantageous embodiments of the invention.

The invention relates, more specifically, to a pipe-gripper adapted for connection to a manipulator for handling a pipe or a pipe stand, characterized by

-   -   a longitudinal housing     -   a rotor which supported in the longitudinal housingis provided         with a U-shaped groove extending axially through it being         supported in a housing and rotatable around the centre axis of         the rotor,     -   a toothed rim being arranged on the periphery of the rotor and         being broken through by the U-shaped groove and being arranged         to be in engagement with a rotor drive via first and second         driving wheels,     -   a distance between a first toothed-ring engagement, formed         between the toothed rim and the first driving wheel, and a         second toothed-ring engagement, formed between the toothed rim         and the second driving wheel, being larger than the width of a         groove mouth, and     -   the rotor being provided with at least one clamping device         provided with at least two diametrically opposite dies which are         radially displaceable into the U-shaped groove and are connected         to a die actuator.

The rotor drive may include a first drive motor which is connected to the first and second driving wheels via first and second transmission means, respectively.

The transmission means may be taken from a group consisting of gear wheels, roller chains and toothed belts.

The toothed rim may be arranged at an end portion of the rotor.

The dies of each clamping device may be displaceable along ramps arranged in the rotor, each ramp having the direction of dip towards the same end portion of the rotor.

Said ramps may dip radially outwards in the axial direction of the rotor away from an, in the vertical position of application of the pipe-gripper, lower end portion of the rotor.

The die actuator may be formed as a second drive motor which is arranged in the housing and is connected via several gear wheels to threaded rods which are each in engagement with a respective die, and a remote-controlled drive coupling forms an interface between the housing and the rotor.

Several clamping devices may be connected to the same die actuator. Alternatively, several clamping devices may be connected to the same die actuator via a resilient coupling element connected to thedies. Alternatively, each clamping device may be connected to a separate die actuator.

BRIEF DESCRIPTION OF THE DRAWINGS

In what follows, an example of a preferred embodiment is described, which is visualized in the accompanying drawings, in which:

FIG. 1 shows, in perspective, a pipe-gripper according to a first embodiment of the invention connected to a manipulator arm;

FIG. 2 shows an axial section through the pipe-gripper according to II-II of FIG. 1;

FIG. 3 shows an axial section through the pipe-gripper according to III-III of FIG. 1;

FIG. 3a shows a section of FIG. 3 on a larger scale;

FIG. 3b shows a section of FIG. 3, in which an alternative embodiment of a connection between a die actuator and a die is shown;

FIG. 4 shows a cross section IV-IV according to FIGS. 2 and 3 on a larger scale;

FIG. 5 shows a cross section V-V according to FIGS. 2 and 3;

FIG. 5a shows a cross section corresponding to that of FIG. 5, but where a rotor has been rotated by 180°;

FIG. 6 shows a longitudinal section VI-VI according to FIG. 3;

FIG. 7 shows a cross section VII-VII according to FIGS. 2 and 3;

FIG. 8 shows in perspective a pipe-gripper according to a second embodiment of the invention;

FIG. 9 shows an isolation perspective view of an embodiment of the pipe-gripper's clamping device;

FIG. 10 shows an axial section view of the pipe gripper according to FIG. 8;

FIG. 11a shows a ground view of an embodiment of the pipe gripper's clamping device; and;

FIG. 11b shows an axial section view XI-XI according to FIG. 11a through the pipe gripper's clamping device.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference is first made to FIG. 1, in which a pipe-gripper 1 according to the invention is connected to a manipulator 2 (shown here just as an end portion of a manipulator arm) arranged to move a pipe or a pipe stand 3. The pipe-gripper 1 includes a longitudinal housing 11 which, in a middle portion 11 a, is provided with a suitable manipulator coupling joint 115. The manipulator arm joint 115 is arranged to move the pipe gripper 1 about a rotation axis 111, allowing the pipe gripper 1 to hold the pipe 3 in positions about the rotation axis 111. The pipe manipulator 2 to which the pipe gripper 1 is attached allows movement of pipe gripper 1 from horizontal to vertical position in a 3-D space. A rotor 12 is supported in first and second rotor bearings 113 a, 113 b projecting from the housing 11. Each rotor bearing 113 a, 113 b is formed as separate supports 114 a defining, at their outer ends, a mouth 114 b and providing both axial and radial fixing of the rotor 12.

The rotor 12, which has a circular periphery 12 c, is provided with a groove 121 extending axially through it, here shown as a U-formed groove, wherefrom, and tangentially to, a semi-circular bottom portion 1211 with a centre axis coinciding with the centre axis of the rotor 12, two parallel side faces 1212 extend to the circular periphery of the rotor, where a groove mouth 1213 is formed.

The end portions 12 a, 12 b of the rotor 12 are each provided with an external toothed rim 122 broken through by the groove 121.

The pipe gripper 1 is provided with a clamp system 123, wherein near the end portions 12 a, 12 b of the rotor 12 according to the embodiment shown in FIG. 1, first and second clamping devices 123 a, 123 b, respectively, are arranged, which are arranged to hold the pipe 3 fixed in the rotor 12. In other embodiments, only one clamp device 123 a may be used. The clamping device 123 a, possibly the clamping devices 123 a, 123 b might even be positioned anywhere along the length of the rotor 12. In diametrically opposite cut-outs 1214 in the rotor 12, guides 1232 are formed in the form of ramps dipping radially outwards in the direction of a second end portion 12 b of the rotor 12, an end portion facing upwards in the normal, operatively vertical position of the pipe-gripper 1. Dies 1231 are arranged to be displaceable in the guides 1232. Each die 1231 is connected to a die carrier 1233 via two articulated arms 1233 a. In the die carrier 1233, a threaded hole 1234 is arranged for receiving a threaded rod 144 (see below).

Reference is now made to FIGS. 2 and 5 in particular. Two rotor drives 13 are arranged in the end portions 11 b, 11 c of the elongated housing 11. Via a drive shaft 131 a, here provided with a toothed wheel 131 b, is engaging with a rotor transmission 139, here shown with several first and second transmission means 132 a, 133 a, shown here as gear wheels, and first and second driving wheels 132, 133, respectively, shown here as toothed wheels, a first drive motor 131 is in engagement with the toothed rims 122 of the rotor 12. The engagements of the first and second driving wheels 132, 133 with the toothed rim 122, form toothed-rim engagements points 1321, 1331 spaced apart by a distance B (see FIG. 5). The distance B is larger than the mouth width A of the rotor 12. A person skilled in the art may choose other forms of rotor transmission 139, for example roller chains or toothed belts and corresponding designs of the drive shaft 131 a and driving wheels 132, 133.

Reference is now made to FIGS. 1, 4, 6 and 7. Arranged in the end portions of the pipe-gripper 1, there are first and second die actuators 14, 14 a which, via a clamp transmission 149 in the form of a drive coupling 142, several gear wheels 143 and threaded rods 144, are each in engagement with a respective clamping device 123 a, 123 b in the rotor 12. A second drive motor 141 is arranged in the housing 11 and is provided with a second drive wheel 145. Via the drive coupling 142 and the gear wheels 143 arranged on the end face of the rotor 12, said drive wheel 145 is in engagement with two threaded rods 144 extending in the axial direction in the rotor 12 into engagement with the threaded holes 1234 of the die carriers 1233 of the respective clamping device 123 a, 123 b.

Even though the exemplary embodiment is shown with a rotor 12 with two toothed rims 122 and two rotor drives 13, the invention may also be practised with a rotor 12 having just one toothed rim 122 and one rotor drive 13.

The rotor 12 may alternatively be provided with just one clamping device 123 a.

The rotor 12 may alternatively be provided with several clamping devices 123 a, 123 b which are connected to one die actuator 14. It is then an advantage if a coupling 1238 between the die actuator 14 and the die carriers 1233 is resilient, for example as shown in FIG. 3b , in which the threaded hole 1234 is arranged in a coupling element 1236 which is placed in a recess 1235 in the die carrier 1233 between two sets of springs 1237, shown as disc springs here. Variations in pipe diameter, die dimensions etc. may thereby be equalized so that all the clamping devices 123 a, 123 b apply roughly the same clamping force to the pipe 3.

The pipe-gripper 1 is connected to the manipulator 2 and wires, not shown, for the supply of energy to the drive motors 131 of the rotor drives 13 and the drive motors 141 and drive couplings 142 of the die actuators 14, 14 a. When the rotor 12 has been rotated in such a way that the groove mouth 1213 coincides with the mouths 114 b of the rotor bearings 113 a, 113 b, the pipe-gripper 1 is moved onto a portion of the pipe 3 which is to be moved. The drive couplings 142 of the die actuators 14, 14 a are activated and the dies 1231 of the clamping devices 123 a, 123 b are moved into engagement with the pipe 3 by the threaded rods 144 being rotated with the respective second drive motors 141. The drive couplings 142 are deactivated so that said second drive motors 141 are uncoupled from the rotor 12.

The manipulator 2 positions the pipe 3 relative to a pipe string not shown, to which the pipe 3 is to be joined. The rotor 12 is put into rotation by means of the first drive motors 131 for joining the pipe 3 and the pipe string not shown. The pipe-gripper 1 is so dimensioned that making up the pipe joint to the prescribed torque is carried out with the pipe-gripper 1. Correspondingly, the pipe-gripper 1 according to the invention can also be used when a pipe joint is to be broken out and a pipe 3 removed from a pipe string.

Reference is now made to FIG. 8, in which pipe-gripper 1′ similar to the pipe gripper 1 of FIG. 1 is shown, however, the pipe gripper 1′ is provided with just on clamp device 123′, here shown with the dies close to the middle of the rotor.

In FIG. 9 is shown a further embodiment of the clamp assembly 123′, in which the clamp device 124′ comprises a clamp housing 330. A clamp drive assembly 320 includes clamp drive 340 wherein a chain or a belt 350 is engaging with drive sprockets 360. The drive sprockets 360 are connected to drive gears 370 positioned in a plane above or below the chain drive sprockets 360. The drive gears 370 engage with clamp drive gears 380. Jack screws 390 are axially extending from respective clamp drive gears 380 and rotates with the clamp drive gears 380. A threaded potion 394 engages with internal threads on a yoke 400. Pistons 420 extend from the yoke 400 in the axial direction of the jack screws 390 and into respective clamp cylinders 430. When then clamp drive 320 is engaged, the pistons 420 is displaced relative to the respective clamp cylinder 430.

Now referring to FIG. 11b , hydraulic discharge ports 432 are depicted. As the pistons 420 are displaced in the clamp cylinders 430, hydraulic fluid is flowing through the hydraulic discharge ports 432. The combined area of bottom portions 434 of the pistons 420 is defined as area C.

Now referring to FIG. 10. Each clamp 124′ includes a die 1231 equivalent to what is described above. The die 1231 may be mechanically coupled to a clamp hydraulic cylinder 310. The clamp hydraulic cylinder 310 is in fluid connection with the clamp cylinder 430 forming a closed-loop hydraulic system. As the pistons 420 are displaced into the clamp cylinders 430, hydraulic fluid is forced from the clamp cylinders 430 through the hydraulic discharge ports 432 into the clamp hydraulic cylinders 310, thereby displacing the dies 1231 towards the centre line of the rotor 12. The dies 1231 may be biased such that, when the pistons 420 are retracted from the clamp cylinders 430, the dies 1231 retracts to their initial positions when hydraulic fluid flows back into the clamp cylinders 430. A die face 312 have an area D. The area D may be greater than area C, such that the force exerted by the die 1231 against the pipe 3 may be greater than that exerted by the pistons 420. The ratio of area D to area C may be between 10:1 and 30:1, more specifically between 15:1 to 25:1.

When the clamping force is sufficient to retain the pipe 3, rotations of the jack screw 390 may cease and the clamp drive 340 is allowed to freewheel, enabling rotation of the rotor 12 without rotating the jack screw 390.

It should be noted that all the above-mentioned embodiments illustrate the invention, but do not limit it, and persons skilled in the art may construct many alternative embodiments without departing from the scope of the attached claims. In the claims, reference numbers in brackets are not to be regarded as restrictive.

The use of the verb “to comprise” and its different forms does not exclude the presence of elements or steps that are not mentioned in the claims. The indefinite article “a” or “an” before an element does not exclude the presence of several such elements.

The fact that some features are indicated in mutually different dependent claims does not indicate that a combination of these features cannot be used with advantage. 

1. A pipe-gripper adapted for connection to a manipulator for the handling of a pipe or a pipe stand, the pipe-gripper comprising: an elongated housing; a rotor supported in the longitudinal housing, and provided with a periphery and provided with a longitudinal groove, the longitudinal groove having an inside face and a groove mouth, the groove mouth having a width, and the rotor being rotatable around its center axis; a toothed rim is arranged on the periphery of the rotor and is interrupted by the longitudinal groove; a clamp assembly comprising at least one clamping device arranged within the rotor; a rotor drive being positioned within the elongated housing; and a rotor transmission in engagement with the rotor drive at toothed-rim engagement points at a distance between the toothed-rim engagement points larger than the width of a groove mouth.
 2. The pipe-gripper according to claim 1, wherein the longitudinal groove has one of a U-shaped, C-shaped, and squared-off cross-section.
 3. The pipe-gripper according to claim 1, wherein the rotor comprises a top clamp assembly and a bottom clamp assembly.
 4. The pipe-gripper according to claim 1, wherein the rotor drive comprises a first drive motor which is connected to the first and second driving wheels via first and second transmission means, respectively.
 5. The pipe-gripper according to claim 1, wherein the rotor transmission is selected from a group consisting of gear wheels, roller chains and toothed belts.
 6. The pipe-gripper according to claim 1, wherein the at least one clamping device provided with at least two diametrically opposite dies which are radially displaceable into the longitudinal groove and are connected to a die actuator.
 7. The pipe-gripper according to claim 6, wherein the dies of each clamping device are displaceable along ramps arranged in the rotor, each ramp having a direction of dip towards the same end portion of the rotor.
 8. The pipe-gripper according to claim 7, wherein said ramp dips radially outwards in the axial direction of the rotor away from a, in the vertical position of application of the pipe-gripper, lower end portion of the rotor.
 9. The pipe-gripper according to claim 6, wherein the die actuator is formed as a second drive motor which is arranged in the housing and is connected via a clamp transmission to threaded rods which are each in engagement with a respective die, and a remote-controlled drive coupling forms an interface between the housing and the rotor.
 10. The pipe-gripper according to claim 1, wherein several clamping devices are connected to the same die actuator.
 11. The pipe-gripper according to claim 1, wherein several clamping devices are connected to the same die actuator via a resilient coupling element connected to the dies.
 12. The pipe-gripper according to claim 1, wherein each clamping device is connected to a separate die actuator. 